JP2000248038A - Polyurethane and leather-like sheet using the same - Google Patents

Abstract

(57) Abstract: The present invention has excellent flexibility and excellent durability such as light resistance and hydrolysis resistance when impregnated and / or applied to a sheet material made of fiber. A polyurethane capable of providing a leather-like sheet, and a leather-like sheet using the same. The polyurethane of the present invention is characterized by containing an ester structure represented by the following chemical formula A in a molecular chain. Embedded image However, n is an integer of 2-8. Further, the leather-like sheet of the present invention is a leather-like sheet containing ultrafine fibers having a fineness of 0.3 dtex or less and polyurethane,
As the polyurethane, at least the above-mentioned polyurethane, and the change in appearance before and after rubbing 10,000 times under the Martindale abrasion test conditions specified in JIS L1906 is 3 or more according to the criterion specified in JIS L1076. It is characterized by the following.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to flexibility, texture,
The present invention relates to a polyurethane having excellent sensibility such as drape property and excellent durability, and a leather-like sheet using the same.

[0002]

2. Description of the Related Art A leather-like sheet obtained by impregnating and / or applying a polymer elastic material to a sheet made of fiber has uniformity, dyeing fastness, and texture flexibility not found in natural leather. And its use has spread to clothing, furniture and seating applications. Higher durability is required as the applications for which it is used expand. In particular, leather-like sheet materials containing ultrafine fibers having a fineness of 0.3 dtex or less and polyurethane are excellent in surface touch and flexibility, but when used for a long period of time, the hair foot becomes partially long, tangled, or hair. There has been a problem that the appearance of the ball changes due to the generation of a ball or the ball breaks. One of the causes is deterioration of the polyurethane. Therefore, studies have been made on a highly durable polyurethane having excellent light resistance and hydrolysis resistance.

For example, with respect to hydrolysis resistance, polyurethane using a polyether diol (hereinafter referred to as polyether polyurethane) is excellent, but has a problem that light resistance is poor. Polyurethane using polyester diol (hereinafter referred to as polyester-based polyurethane) is excellent in light resistance but poor in hydrolysis resistance. Polyurethanes using polycarbonate diol (hereinafter referred to as polycarbonate-based polyurethanes) are excellent in both light resistance and hydrolysis resistance, but have a problem that the leather-like sheet obtained due to hardness is plastic-like. Polyurethanes obtained by mixing and / or copolymerizing these polyurethanes have a better balance of light resistance and hydrolysis resistance than individual polyurethanes alone, but still have overall durability. Insufficient.

[0004] Also, Japanese Patent Application Laid-Open No. 61-185520,
JP-A-62-2817 discloses a condensate of a diol mainly composed of 1,9-nonanediol and / or 2-methyl-1,8-octanediol and a dicarboxylic acid having an average molecular weight of 700 to 4000. It is disclosed that durability and flexibility are improved by a polyurethane having a polyester as a soft segment and a leather-like sheet using the same. This is based on the fact that a polyester diol comprising a diol having a relatively large number of carbon atoms is excellent in hydrolysis resistance, and furthermore, having a side chain reduces intermolecular force and improves flexibility. However, even in this polyurethane, the effect is small because the side chains are shorter than the length of the main chain, and the flexibility is still insufficient. Further, although the durability is superior to that of the conventional product, when the polyurethane is used for a long period of time, the decomposition of the polyurethane proceeds, and the appearance changes and tears occur. In other words, although the durability improvement of the conventional polyester-based polyurethane is achieved to some extent by the above polyurethane,
Durability and flexibility were still inadequate, indicating the limitations of such polyester-based polyurethanes. Accordingly, there is a need for a polyurethane that can achieve both higher levels of durability and flexibility.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet-like material made of fibers which has excellent flexibility and excellent durability such as light resistance and hydrolysis resistance when impregnated and / or coated. Another object of the present invention is to provide a polyurethane from which a leather-like sheet can be obtained and a leather-like sheet using the same. Another object of the present invention is to provide clothing, furniture, car seats, bags, gloves, and the like having both excellent durability and flexibility.

[0006]

The present invention employs the following means in order to solve the above-mentioned problems. That is, the polyurethane of the present invention has the following chemical formula A
Is contained in the molecular chain.

[0007]

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Here, n is an integer of 2 to 8.

The leather-like sheet of the present invention is a leather-like sheet containing ultrafine fibers having a fineness of 0.3 dtex or less and polyurethane, wherein the polyurethane contains at least the polyurethane and JIS L19.
100 under the Martindale wear test conditions specified in
The appearance change before and after rubbing 00 times is JIS L1
076, wherein the number is 3 or more.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is intended to improve the flexibility and the light resistance, the hydrolysis resistance and the like when impregnated and / or applied to a sheet made of fiber. After diligently examining the polyurethane that can provide an excellent leather-like sheet, we tried to adopt a polyurethane with a specific ester structure included in the molecular chain, and found that this problem could be solved at once. is there.

First, the ester structure of the following chemical formula A will be described.

[0012]

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This ester structure has 2,4-diethyl-
Polyester obtained by polycondensing 1,5-pentanediol with an aliphatic dicarboxylic acid or an ester-forming derivative thereof. Polyurethanes having a special structure made of such polyesters have unprecedented light resistance, hydrolysis resistance and flexibility. This is because 2,4-diethyl-1,5-pentanediol has a relatively large number of carbon atoms and is hydrophobic, so that it is difficult to hydrolyze, and the total number of carbon atoms in the two side chains is comparable to the number of carbon atoms in the main chain. It is thought that the intermolecular force is hard to work and the molecules are easy to move, so that flexibility is developed.

Further, such a polyurethane is not only excellent in light resistance and hydrolysis resistance, but when it is used to form a leather-like sheet, even if the polyurethane decomposes to some extent, it breaks or changes in appearance. Has the characteristic that hardly occurs. The reason for this is not clear, but the durability of the leather-like sheet made of fiber and polyurethane
Factors that affect flexibility include adhesion between polyurethane and fibers, distribution state of polyurethane, and the like, in addition to the stability of polyurethane itself, and it is considered that these influences.

Further, regarding the aliphatic dicarboxylic acid, n
Is larger than 9, the cold resistance, flexibility and the like are deteriorated. On the other hand, if n is too small, the hydrolysis resistance is reduced. Therefore, adipic acid in which n is 2 to 8, particularly 4 is preferable.
That is, a polyurethane having a special structure constituted by a polyester represented by the following chemical formula B is preferable.

[0016]

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These aliphatic dicarboxylic acids or their ester-forming derivatives can be used alone or in combination of two or more as required. Also,
As long as the object of the present invention is not impaired, an aliphatic dicarboxylic acid in which n is larger than 9 or an ester-forming derivative thereof can be mixed and used.

Further, it is a raw material of such polyurethane.
If the molecular weight of the polyester diol using 2,4-diethyl-1,5-pentanediol is 500 or less, the feel becomes hard, and if it is 3000 or more, the durability is lowered. Therefore, 500 to 3000 is preferable.

In the present invention, the structure derived from the polymer diol includes a structure other than the structures represented by the chemical formulas A and B as long as the desired flexibility and durability are satisfied. It doesn't matter. Examples of such a structure include an ester structure derived from polyethylene adipate and polyoctamethylene adipate, and a carbonate structure derived from polyhexamethylene carbonate and the like.Especially, an ether structure represented by the following chemical formula C, Polyurethane comprising at least one structure selected from the group consisting of an ester structure represented by D, an ester structure represented by the following chemical formula E, and a carbonate structure represented by the following chemical formula F in a molecular chain: It has an excellent balance between durability and flexibility, and is one of the more preferred embodiments of the present invention.

[0020]

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[0021]

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[0022]

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[0023]

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These polyurethanes having a plurality of structures have excellent flexibility and durability which cannot be imagined from polyurethanes each having only a single structure.

In order to introduce the structures represented by the chemical formulas C to F into a polyurethane, a polyester diol using 2,4-diethyl-1,5-pentanediol and a polytetramethylene Glycol, polycaprolactone diol, polyneopentyl adipate diol, and polyhexamethylene carbonate diol may be used in combination. In some cases, in forming a polyester diol from 2,4-diethyl-1,5-pentanediol, a copolymerized polyester diol obtained by mixing corresponding monomers may be used. When the molecular weight of these polymer diols is 500 or less, the texture becomes hard, and when the molecular weight is 3000 or more, the durability is reduced.

The ratio of the structures represented by the chemical formulas A and B and the structures represented by the chemical formulas C, D, E and F is not particularly limited, and the ratio is set to 4: 1 to 1: 4. durability,
It can be appropriately selected according to the flexibility.

The diisocyanate used in combination with these diols is not particularly limited, and those generally used for the synthesis of polyurethane can be appropriately selected and used. For example, if heat resistance is important,
Aromatic diisocyanates such as 4'-diphenylmethane diisocyanate can be used. If it is desired to suppress yellowing due to NOx or light, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 1,6-hexamethylene diisocyanate, etc. Alicyclic diisocyanate and aliphatic diisocyanate can be used. Further, a plurality of these diisocyanates may be used as a mixture depending on the purpose.

The chain extender is not particularly limited, and a chain extender used in the production of ordinary polyurethane, that is, a low molecular compound having two or more active hydrogens can be used. Examples thereof are aliphatic glycols such as ethylene glycol, propylene glycol, 1,6-hexanediol, etc., polyalkylene glycols such as diethylene glycol, dipropylene glycol, ethylenediamine, aliphatic such as isophoronediamine, and alicyclic diamines. Aromatic diamines such as methylenebisaniline can be used alone or as a mixture.

In particular, 4,4'-
When diphenylmethane diisocyanate and an aliphatic diol having 2 to 8 carbon atoms, particularly ethylene glycol, are used as a chain extender, a polyurethane excellent in durability and flexibility can be obtained. The method for producing the polyurethane of the present invention is not particularly limited, and examples thereof include a method in which a polymer diol and a diisocyanate are first reacted to form a prepolymer and then reacted with a chain extender as in a conventional method.

The ratio between the polymer diol and the diisocyanate at this time is not particularly limited, and the polymer diol may be increased when flexibility is emphasized, and the diisocyanate is increased when durability is emphasized. It is preferable to mix them so that the molar ratio is 1: 2 to 1: 5. When a plurality of polymer diols and diisocyanates are used, they may be separately reacted to form a plurality of prepolymers in advance, mixed and reacted with a chain extender to obtain a structure close to a block copolymer, In this state, a prepolymer may be prepared and reacted with a chain extender to obtain a structure close to a random copolymer. Further, as a catalyst for these reactions, an organic tin compound, an organic titanium compound, a tertiary amine or the like can be added.

The leather-like sheet according to the present invention comprises ultrafine fibers having a fineness of 0.3 dtex or less and the above-mentioned polyurethane.
The appearance change before and after rubbing 10,000 times under the conditions of the 6th Martindale wear test is 3 or more according to the criterion of JIS L1076, and is preferably (1) JISB7.
After irradiating light for 100 hours with a sunshine carbon arc lamp-type light resistance tester of the 753 standard, (2) leaving it in an atmosphere of a temperature of 70 ° C. and a relative humidity of 90% for one week,
It is characterized in that the appearance change before and after the above-mentioned Martindale abrasion test after performing (1) and (2) in this order is 3 or more according to the criterion of JIS L1076.

As the acceleration evaluation of such a leather-like sheet, measurement of the physical properties after performing the treatments (1) and (2) alone has been performed so far. However, there is no correlation between the evaluation means and the durability when actually used, and even though the decrease in physical properties when each treatment is performed independently is small, the durability when actually used is small. In many cases the gender was insufficient.

Therefore, in the present invention, these (1),
It has been determined that the physical properties after continuous (rather than separately performing the treatment of (2)) can be more compatible with the durability when actually used, and the polyurethane of the present invention It has been found that when using a leather-like sheet, a leather-like sheet having a small change in appearance even after such forced deterioration shows excellent durability even in actual use.

The types of leather-like sheet materials are roughly classified into two types, namely, pilling and fluffing. The degree of contribution differs depending on the type of leather-like sheet material. Out, pilling,
Adopt a worse grade than fluff.

In order to obtain a leather-like sheet which satisfies the conditions of the present invention, it is preferable to use the polyurethane of the present invention and ultrafine fibers, and to adjust the amount of polyurethane to be attached. The amount of adhesion is adjusted by the fineness of the ultrafine fibers and the density of the sheet-like material, but the ratio of the polyurethane to the ultrafine fibers is preferably in the range of 1: 5 to 2: 1. When the ratio is 1: 4 or less, the physical properties and durability are insufficient, and the ratio is 2: 1.
If it exceeds, the texture will be hard.

The density of the leather-like sheet is not particularly limited, but if it is 0.2 g / cm ³ or less, the durability tends to decrease, and if it is 0.6 g / cm ³ or more, the flexibility tends to decrease. Therefore, it is desirable to be 0.2 to 0.6 g / cm ³ .

The material of the ultrafine fibers having a fineness of 0.3 dtex or less according to the present invention is not particularly limited, and examples thereof include polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polypropylene terephthalate, and polyamides such as nylon 6 and nylon 6,6. be able to.

The fineness is 0.3 d in terms of flexibility and quality.
tex or less, but in the case of polyester, 0.3 to
0.01 dtex, 0.1 to 0.0 for polyamide
01 dtex is preferred.

Further, these ultrafine fibers can be used as a mixture, and may be used within a range not to impair the object of the present invention.
Fibers thicker than 3 dtex may be mixed. Also, the cross-sectional shape of the fiber may be a normal round cross-section,
In addition, a so-called triangular or + -shaped so-called irregular cross section can be used.

As a method for obtaining such an ultrafine fiber, a method for directly obtaining an intended ultrafine fiber or a method for once preparing a thick fiber,
After that, there is a method of expressing ultra-fine fibers, but in terms of the ease with which fine fibers can be obtained and the flexibility of the obtained leather-like sheet-like material, once a thick fiber is created, and then the method of expressing ultra-fine fibers is preferable.

An example of such a method is a method in which a plurality of polymers having different solubilities are spun together to obtain a fiber capable of expressing microfine fibers, and then at least one polymer is removed to form microfine fibers. Can be mentioned.

Examples of the composite form when spinning the polymer include a so-called side-by-side type in which the polymers are bonded to each other, a sea-island type in which another polymer is relatively uniformly present in the form of an island, and a polymer. A blend type mixed in an alloy shape can be employed.

The types of polymers to be removed include polyolefins such as polyethylene and polystyrene, sodium sulfoisophthalic acid and polyethylene glycol,
For example, a copolymerized polyester having a higher alkali solubility by copolymerizing the same can be used.

The thus obtained fibers capable of expressing ultrafine fibers are formed into a sheet, and subjected to polyurethane treatment and ultrafine fiber expression treatment. In addition, a leather-like sheet-like material is obtained by performing processes such as gluing, pressing, buffing, coating, and dyeing as necessary.

Examples of sheeting of fibers capable of expressing ultrafine fibers include woven fabrics, knitted fabrics, nonwoven fabrics, and composites thereof. Usual plain weave or twill weave can be used as the woven fabric, and knitting or tubular knitting can be used as the knitted fabric. The non-woven fabric may be either a short-fiber non-woven fabric or a long-fiber non-woven fabric, but if importance is placed on the feel and quality, the short-fiber non-woven fabric is preferred.

Examples of a method for obtaining a short fiber nonwoven fabric include a method using a card, a cross wrapper, and a random webber, and a papermaking method. Further, the nonwoven fabric obtained by these methods can be entangled with a needle punch or a water jet punch, or can be integrated with another woven fabric, knitted fabric or nonwoven fabric. Further, a sizing agent such as polyvinyl alcohol and a binder such as polyacrylamide and polyurethane can be provided as necessary.

The method for developing the ultrafine fibers differs depending on the type of the component to be removed. For a polyolefin such as polyethylene or polystyrene, an organic solvent such as toluene or trichloroethylene is used. For a copolyester, an aqueous alkali solution such as sodium hydroxide is used. A method of performing immersion and squeezing liquid can be exemplified.

It is necessary to impregnate the sheet thus obtained with the polyurethane solution of the present invention and to coagulate the polyurethane. DMF, DMSO, or the like can be used as a solvent for the polyurethane. Further, other solvents and water can be added as long as the solubility of the polyurethane is not hindered. Further, a coagulation regulator such as a higher alcohol or a surfactant can be added for the purpose of controlling the coagulation structure of the polyurethane. Further, a pigment, an ultraviolet absorber and an antioxidant may be added as necessary, and a stabilizer such as an ultraviolet absorber and an antioxidant may be copolymerized as necessary.

In addition, one of the important factors affecting the durability and flexibility of the leather-like sheet of the present invention is the solidified structure of polyurethane in the leather-like sheet.
The solidified structure can be broadly classified into two types: a dispersed / scattered structure (hereinafter referred to as a dispersed structure) and a connected / integrated structure (hereinafter referred to as a connected structure). Comparing the two, the dispersed structure is advantageous for flexibility but disadvantageous for durability, and conversely, the connection structure is disadvantageous for flexibility but advantageous for durability. The polyurethane of the present invention has a feature that it tends to have a microporous structure in which a large number of micropores are present inside, and this may be one of the causes of obtaining a leather-like sheet having excellent durability and flexibility. thinking. Further, the solidified structure needs to be adjusted according to the target level of durability and flexibility. One means for this is to optimize the coagulation rate of the polyurethane by adjusting the coagulation conditions. The coagulation conditions in that case are the temperature of the coagulation bath,
The presence or absence (and the concentration) of an organic solvent such as DMF and DMSO to be added to the coagulation bath is exemplified.

[0050]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to examples, but the present invention is not limited to these examples.

The meanings of the abbreviations used in the examples and comparative examples are as follows. EG: ethylene glycol DMF: N, N'-dimethylformamide MBA: methylenebisaniline MDI: 4,4'-diphenylmethane diisocyanate DEPG: 2,4-diethyl-1,5-pentanediol PDEPA: 2,4-diethyl-1 Polyester diol obtained by condensing adipic acid with 1,5-pentanediol and adipic acid PNA: Polyester diol obtained by condensing a 9: 1 mixture of 1,9-nonanediol and 2-methyloctanediol with adipic acid PCL: Polycaprolactone diol PHC : Polyhexamethylene carbonate diol PTMG: polytetramethylene glycol The evaluation method of the present example and comparative example is as follows. <Durability> Jumbar-like wearing samples were prepared from each leather-like sheet to be evaluated. As a monitor, an adult man mainly engaged in office work was selected, and normal work was performed with a wearing sample always worn. In order to eliminate the difference in usage between monitors, worn samples were exchanged and rotated between monitors every week, and further cleaned with petroleum solvents every 5 weeks. After the completion of 25 weeks, the sample was comprehensively evaluated for changes in appearance, presence or absence of tears, and the like. <Flexibility> Five testers who had at least three years of experience developing textile products were evaluated on a 10-point scale, with 10 being the highest and 6 or more being acceptable, and the average score was used. <Martindale abrasion test> A sample for measurement was randomly sampled from four places from a leather-like sheet having a size of about 1 mx 1 m, and rubbed 10,000 times under furniture conditions in the Martindale abrasion test specified in JIS L1906. Was evaluated according to JIS L1076 standard. When there was a difference in judgment between the four samples, the sample with the worst number was adopted. <Forced degradation processing> The following processing was performed in the order of (1) and (2).

(1) Light irradiation with a sunshine carbon arc lamp type light resistance tester specified in JIS B7753 for 100 hours (2) Leaving for 1 week in an atmosphere of a temperature of 70 ° C. and a relative humidity of 90% Example 1 Condensation of DEPG and adipic acid PDEPA having a number average molecular weight of 2,000 obtained by polymerization and PHC having a number average molecular weight of 2,000 were mixed at a ratio of 70:30, and MD
After reacting with I at 60 ° C. for 6 hours, the mixture was diluted to 40% with DMF, MBA was added and reacted at 40 ° C. for 6 hours to obtain a polyurethane solution.

The polyurethane solution thus obtained was diluted with DMF so that the solid content became 15% by weight, and 2% by weight of sorbitan monostearate was added as an additive to prepare a polyurethane impregnating solution.

Separately, sea-island composite fibers were prepared using a sea-island type composite yarn base. The compound conditions are as follows. Sea component: polystyrene Island component: polyethylene terephthalate Sea-island ratio: 25% sea, 75% island The sea-island composite fiber was stretched 3.2 times, further crimped, and then cut to obtain raw cotton. The raw cotton was formed into a web using a cross wrapper, and further subjected to needle punching to obtain a nonwoven fabric. After impregnating the nonwoven fabric with 10% polyvinyl alcohol solution, it was squeezed and dried. Thereafter, the sea component was extracted with trichlorethylene to obtain a fiber sheet made of ultrafine fibers of 0.09 dtex.

The fibrous sheet was immersed in the above-mentioned polyurethane impregnating liquid, and the amount of the polyurethane impregnating liquid applied was adjusted with a squeezing roll. Then, the polyurethane was coagulated in a 30% DMF aqueous solution. Then, add DM water with 85 ° C hot water.
After removing F and polyvinyl alcohol, immediately pressing and drying, the sheet was subjected to a raising treatment, and then dyed with a disperse dye to obtain a leather-like sheet.

The appearance change before and after rubbing this sheet-like material 10,000 times under the Martindale abrasion test conditions specified in JIS L1906 was 3 according to the criterion specified in JIS L1076.
No. In addition, after the forced deterioration, the appearance change when abrasion test was performed similarly was No. 3. Table 1 shows the durability and flexibility of the obtained leather-like sheet. Comparative Example 1 A polyurethane solution and a leather-like sheet using the same were obtained in the same manner as in Example 1, except that PCL having a number average molecular weight of 2000 was used instead of PDEPA.

The appearance change before and after the sheet was rubbed 10,000 times under the Martindale abrasion test conditions specified by JIS L1906 was 3 according to the criterion specified by JIS L1076.
No. In addition, after the forced deterioration, the appearance change when the abrasion test was similarly performed was No. 1. Table 1 shows the durability and flexibility of the obtained leather-like sheet. Comparative Example 2 PTMG having a number average molecular weight of 2000 instead of PDEPA
A polyurethane solution and a leather-like sheet using the same were obtained in the same manner as in Example 1 except that the above-mentioned was used.

The appearance change before and after rubbing the sheet-like material 10,000 times under the Martindale abrasion test conditions specified in JIS L1906 was 3 according to the criterion specified in JIS L1076.
No. In addition, after the forced deterioration, the appearance change when the abrasion test was similarly performed was No. 1. Table 1 shows the durability and flexibility of the obtained leather-like sheet. Comparative Example 3 Instead of PDEPA, a number-average molecular weight of 200 obtained by subjecting adipic acid to condensation polymerization with a 9: 1 mixture of 1,9-nonanediol and 2-methyloctanediol was used.
Except for using PNA of 0, in the same manner as in Example 1,
A polyurethane solution and a leather-like sheet using the same were obtained.

The appearance change before and after the sheet was rubbed 10,000 times under the Martindale abrasion test conditions specified in JIS L1906 was 3 criterion according to JIS L1076 specified.
No. In addition, after the forced deterioration, the appearance change when abrasion test was performed similarly was No. 2. Table 1 shows the durability and flexibility of the obtained leather-like sheet. Comparative Example 4 Without mixing PDEPA, except using only PHC,
In the same manner as in Example 1, a polyurethane solution and a leather-like sheet using the same were obtained.

The appearance change before and after rubbing the sheet-like material 10,000 times under the Martindale abrasion test conditions specified by JIS L1906 was 4 according to the criterion specified by JIS L1076.
No. In addition, after the forced deterioration, the appearance change when abrasion test was performed similarly was No. 3. Table 1 shows the durability and flexibility of the obtained leather-like sheet. Comparative Example 5 Instead of PDEPA, a number-average molecular weight of 200 obtained by subjecting a 9: 1 mixture of 1,9-nonanediol and 2-methyloctanediol to adipic acid by condensation polymerization.
Except for using PNA of 0, in the same manner as in Example 1,
A polyurethane solution and a leather-like sheet using the same were obtained.

The appearance change before and after rubbing the sheet-like material 10,000 times under the Martindale abrasion test conditions specified in JIS L1906 was 4 according to the criterion specified in JIS L1076.
No. In addition, after the forced deterioration, the appearance change when the abrasion test was similarly performed was No. 3. Table 1 shows the durability and flexibility of the obtained leather-like sheet. Example 2 Polyester diol having a number average molecular weight of 2000 and PTMG having a number average molecular weight of 1500 obtained by condensation polymerization of DEPG and adipic acid were mixed at a ratio of 40:60, and reacted with MBA at 60 ° C. for 6 hours. Later, DMF
To 40%, MBA was added and reacted at 30 ° C. for 6 hours to obtain a polyurethane solution. The polyurethane solution thus obtained was diluted with DMF so as to have a solid content of 14% by weight to prepare a polyurethane impregnating liquid.

Separately, blend type composite fibers were prepared by a chip blending method. The compound conditions are as follows. Sea component: Low-density polyethylene Island component: Nylon 6 Sea-island ratio: 30% sea, 70% island The sea-island composite fiber was stretched 3.0 times, further crimped, and then cut to obtain raw cotton. The raw cotton was formed into a web using a cross wrapper, and further subjected to needle punching to obtain a nonwoven fabric. This nonwoven fabric was immersed in the above-mentioned polyurethane impregnating liquid, and the amount of the polyurethane impregnating liquid applied was adjusted with a squeezing roll. Then, the polyurethane was coagulated in a 30% DMF aqueous solution. Thereafter, DMF was removed with hot water at 85 ° C., and immediately after pressing and drying, the sea component was extracted with toluene at 80 ° C. to obtain a fibrous sheet made of ultrafine fibers having an average of 0.005 dtex. After raising the sheet, the sheet was dyed with a disperse dye to obtain a leather-like sheet.

The appearance change before and after rubbing the sheet-like material 10,000 times under the Martindale abrasion test conditions specified in JIS L1906 was 4 according to the criterion specified in JIS L1076.
No. In addition, after the forced deterioration, the appearance change when abrasion test was performed similarly was No. 3. Table 1 shows the durability and flexibility of the obtained leather-like sheet. Example 3 A polyurethane solution and a leather-like sheet using the same were obtained in the same manner as in Example 1 except that EG was used instead of MBA.

The appearance change before and after rubbing the sheet-like material 10,000 times under the Martindale abrasion test conditions specified in JIS L1906 was 4 by the criterion specified in JIS L1076.
No. In addition, after the forced deterioration, the appearance change when abrasion test was performed similarly was No. 3. Table 1 shows the durability and flexibility of the obtained leather-like sheet. Comparative Example 6 A polyurethane solution and a leather-like sheet using the same were obtained in the same manner as in Example 3 except that the concentration of the polyurethane impregnating liquid was 11%.

The appearance change before and after rubbing the sheet-like material 10,000 times under the Martindale abrasion test conditions specified by JIS L1906 was 2 according to the criterion specified by JIS L1076.
No. In addition, after the forced deterioration, the appearance change when the abrasion test was similarly performed was No. 1. Table 1 shows the durability and flexibility of the obtained leather-like sheet.

[0066]

[Table 1]

As is clear from Table 1, the products of Examples 1 to 3 are superior in durability or flexibility to those of Comparative Examples 1 to 5, and the polyurethanes and leathers of the present invention are excellent in durability and flexibility. It can be seen that these two properties can be satisfied by the sheet-like material.

[0068]

According to the present invention, a polyurethane having excellent durability and flexibility and a leather-like sheet made of the same can be provided. Such a leather-like sheet material,
It can be suitably used as a material for clothing, furniture, car seats, bags, gloves and the like.

Continued on the front page F-term (reference) 4F055 AA01 AA27 BA12 BA16 CA15 EA11 FA15 FA19 4J034 CA01 CA03 CA04 CA12 CA15 CB03 CC01 CC02 CC03 CC08 CC11 CC12 CC26 CC45 CC52 CC61 CC62 CC65 DF01 DF03 DF12 DF14 DF20 HA01 HC02 HC03 HC11 HC12 HC22 HC46 HC52 HC63 HC64 HC66 HC67 HC71 HC73 QA05 RA09

Claims (6)

[Claims] 1. A polyurethane comprising an ester structure represented by the following chemical formula A in a molecular chain. Embedded image However, n is an integer of 2-8. 2. The polyurethane according to claim 1, wherein the ester structure represented by the chemical formula A is an ester structure represented by the following chemical formula B. Embedded image 3. An at least one selected from the group consisting of an ether structure represented by the following chemical formula C, an ester structure represented by the following chemical formula D, an ester structure represented by the following chemical formula E, and a carbonate structure represented by the following chemical formula F: 3. The polyurethane according to claim 1, wherein the polyurethane contains various kinds of structures in a molecular chain. Embedded image Embedded image Embedded image Embedded image 4. The polyurethane according to claim 1, wherein the polyurethane contains 4,4-diphenylmethane diisocyanate as a diisocyanate component and an aliphatic diol having 2 to 8 carbon atoms as a chain extender. The described polyurethane. 5. A leather-like sheet containing ultrafine fibers having a fineness of 0.3 dtex or less and polyurethane, wherein the polyurethane contains at least 30% by weight of the polyurethane according to any one of claims 1 to 4, And JIS
The appearance change before and after rubbing 10,000 times under the Martindale abrasion test conditions specified in L1906 was measured according to JIS.
A leather-like sheet material characterized by No. 3 or more in a judgment criterion specified in L1076. 6. After performing forced deterioration processing under the following conditions, JI
The appearance change before and after rubbing 10,000 times under the Martindale abrasion test conditions specified in
6. The leather-like sheet according to claim 5, wherein the number is 3 or more according to a criterion specified in IS L1076. Forced deterioration processing: The following processing is performed in the order of (1) and (2). (1) Irradiation with light for 100 hours using a sunshine carbon arc lamp type light resistance tester specified in JIS B7753 (2) Left for 1 week in an atmosphere at a temperature of 70 ° C. and a relative humidity of 90%